Sudden cardiac arrest (SCA) occurs every 2 minutes throughout the US; most, >70%, occur at home. Because survival falls 10% per minute over the first 10 minutes, it is imperative to defibrillate as close to time zero as possible. Public efforts cannot provide defibrillation fast enough in most cases. We believe the initial shock is best done by the family only seconds from their loved one using readily available automatic external defibrillators (AEDs). AEDs are now simple enough to use that extensive training is no longer required for effective use. Our central hypothesis is that provision of an AED for home use will improve survival beyond that achieved from the typical lay response to SCA. We will test our hypothesis by prospectively randomizing 7,000 patients following anterior myocardial infarction (MI) either to standard lay response to SCA (call emergency medical service (EMS) systems/CPR) or to add the use of a home AED to the standard response. The standard response will be augmented and standardized by the provision of a video on how to respond to SCA and how to perform CPR. Our goal for the standard response is immediate notification of EMS and prompt CPR. Our goal for AED is to shock twice immediately, if indicated by the AED, and call EMS and perform CPR as soon as possible and preferably within 2 minutes of collapse. Although many types of cardiac disease patients are at rick of SCA and could be appropriate candidates for this trial, we chose anterior MI patients, with precordial Q-waves on ECG, primarily because of modest screening costs, ease of identification, and sufficient risk to test the hypothesis. The 7,000 patient population size is dependent upon the assumption that anterior MI patients will have a risk of death of approximately 4% yearly. Patients will be enrolled over 2+ years and followed for an additional 2 years. We hypothesize that mortality will be reduced by 20% in the AED group. The study is powered at 90% with an alpha of 0.05. Treatment arms will be compared using an intention-to-treat analysis. We have one primary specific aim: To compare all-cause mortality in the two arms of the trial. The study will be performed at 200 cardiology clinics and have the acronym HAT for Home AED Trial. Trial management will be by Drs. Gust Bardy, Roger White, Kerry Lee, Melanie Dowdell, WT Longstreth, Jr, Daniel Mark, Douglas Packer, and Jeanne Poole.